This application is a 371 of PCT/JP00/02716 filed Apr. 26, 2000.
The present invention relates to a cannabinoid removal material and to a cannabinoid removal column in which this is employed. In particular, by enabling cannabinoids to be eliminated from human blood, the invention is suitably employed in applications to ameliorate sepsis and other such medical conditions, or in applications to ameliorate symptoms of hypotension brought about by raised cannabinoid concentrations in the blood of 500 pg/ml or above, and especially 1 ng/ml or above.
It has become clear that cannabinoids, which may be termed endogenous marihuana, can be induced/expressed by means of lipopolysaccharide (hereinafter abbreviated to LPS). Cannabinoids are said to cause psychoneural symptoms (consciousness modification, etc) via CB1 receptors expressed in the brain, and also to cause hypotension and immunodeficiency via CB1 and CB2 expressed peripherally. A recent publication (The FASEB Journal, Vol.28: 1035 1998) describes the fact that LPS, by acting on platelets and macrophages, brings about expression and release of 2-arachidonylglycerol and anandamide, which are respectively types of cannabinoid, and these bring about hypotensive shock. Furthermore, in a rat endotoxaemia model, it has been shown that hypotensive shock can be prevented by blocking cannabinoids based on CB1 receptor antagonists. For these reasons, it can be concluded that cannabinoids play an important role in endotoxin shock.
Consequently, the removal of cannabinoids can be expected to be effective in the amelioration of hypotensive shock produced by cannabinoids.
The present invention has as its objective to provide a material for removing the cannabinoids which cause such hypotension and immunodeficiency, etc, together with a removal column wherein this material is employed.
To resolve the aforementioned problem, the present invention has the following constitution:
A material for the removal of cannabinoids in body fluids where there is immobilized on a water-insoluble carrier a substance with functional groups capable of hydrogen bonding, for example a substance having cationic functional groups and/or a physiologically active substance, and preferably a substance also having hydrophobic groups; and a cannabinoid removal column which is characterized in that it incorporates said removal material.
The present invention offers a material enabling cannabinoids to be removed. In the present invention, the term cannabinoids refers to generally known cannabinoids and denotes substances capable of bonding with cannabinoid receptors (CB1 and CB2), including marihuana-derived cannabinoids and endogenous cannabinoids. While there are no particular restrictions, there can be cited as examples anandamide (arachidonylethanolamide), 2-arachidonylglycerol (hereinafter abbreviated to 2-AG), cannabinol, cannabidiol, xcex949-tetrahydrocannabinol, levonantranol, nabilone, 6-S-[3(R),6xcex1,6axcex1,9xcex1,10axcex2]-(xe2x88x92)-5,6,6a,7,8,9,10,10a-octahydro-6-methyl-3-(1-methyl-4-phenylbutoxy)-1,9-phenanthridinediol 1-acetate hydrochloride and R-(+)-(2,3-hydro-5-methyl-3-[4-morponolinylmethyl]pyrrole[1,2,3-de]-1,4-benzoxalin-6-yl(1-naphthalenyl)naphthanone mono-methanesulphonate. Furthermore, cells incorporating cannabinoids, for example, platelets and macrophages, etc, are also included. Again, cannabinoids bound to lipid, albumin and other such serum components are included.
As examples of lipids which bind cannabinoids there are simple lipids, which are merely the esters of alcohols and fatty acids, and complex lipids comprising phospholipids, lipoproteins (chylomicrons, VLDL, LDL, HDL, VHDL), and the like.
As examples in the present invention of the functional groups capable of hydrogen bonding, there are cationic functional groups, carboxyl groups, sulphate ester groups, sulphonic acid groups, phosphoric acid groups, hydroxyl groups, thiol groups, aldehyde groups, carbonyl groups, urea bonds, thiourea bonds and the like.
As examples of cationic functional groups, there are primary amino groups, secondary amino groups, tertiary amino groups, imino groups, quaternary ammonium groups, amide groups and the like.
As examples of hydrophobic functional groups, there are alkyl groups, aromatic groups and the like.
Synthetic polymers such as polystyrene, polypropylene, polyamide, polyimide, poly(aromatic vinyl compounds), polyester, polymethyl methacrylate, polysulfone, polyethylene, polyvinyl alcohol, polytetrafluoroethylene and the like, and natural polymers including cellulose, collagen, chitin, chitosan, dextran and derivatives thereof, are suitably used as the insoluble carrier material employed in the present invention. Furthermore, materials comprising a metal, ceramic, glass or other such inorganic material coated with a suitable polymer and where the surface has been directly modified, are also suitably used.
The material of the present invention may have the form of fibre, hollow fibre, beads, flat film or powder, etc, but a fibre, hollow fibre or bead-form material suitable for the extracorporeal circulation of whole blood, which is circulated in a column without separating the blood corpuscles and plasma, is particularly preferred. To increase the percentage adsorption, a porous material of large contact area is preferred. Furthermore, in the case of beads, these should show little pressure loss when packed in a column and have a large surface area, so beads of diameter in the range 50-1000 xcexcm are preferred, with a diameter in the range 200-700 xcexcm being further preferred.
There are no particular restrictions on the components of a fibre material but polystyrene fibre, crosslinked polystyrene fibre, acrylic acid/acrylonitrile copolymer fibre or carboxyl group-containing polyvinyl alcohol fibre is preferably used, in that the introduction of functional groups is particularly easy. Furthermore, from the point of view of processability and durability, so-called islands-in-a-sea type fibre, where reinforcement is effected by the islands component, is preferably used, for example islands-in-a-sea type fibre employing polystyrene as the sea component and polypropylene or the like as the islands component.
Regarding the surface area of the fibre material, on the assumption that it is to be used in extracorporeal circulation a material having a surface area in the range 0.1-100 m2/g is preferred. The surface area is measured by the BET method.
Reference to a physiologically active substance in the present invention means a polypeptide, polysaccharide, nucleic acid or the like and specific examples are polymyxin, vancomycin, actinomysin, viomysin, albumin and protein A, etc. Polymyxin is an antibiotic produced by Bacillus polymyxa, and there are types such as polymyxin A, polymyxin B, polymyxin D and polymyxin E. It has an antimicrobial action against gram-negative bacteria.
The cannabinoid adsorption is strongly influenced by the cannabinoid concentration and by the proportions of the carrier to cannabinoid solution. The cannabinoid adsorption is expressed by the percentage adsorption, in terms of 50 mg of fibre-form material or 200 xcexcl of bead-form material, when reaction is carried out at 37xc2x0 C. for 2 hours with 1 ml of normal human serum to which a 1 xcexcg/ml concentration of cannabinoid is added. To determine the percentage cannabinoid adsorption, either the cannabinoid which has been adsorbed onto the carrier is measured after elution from the carrier, or the cannabinoid remaining in the serum is measured. As a result, based on 50 mg of material in the form of fibre or 200 xcexcl in the form of beads, materials which adsorb and remove at least 200 ng (20%) of the cannabinoid are preferred, and those which adsorb and remove at least 300 ng (30%) of the cannabinoid are further preferred.
Cannabinoid can be removed by passing a treatment liquid containing the cannabinoid through a column packed with the above-mentioned cannabinoids removal material. As the treatment liquid, there is used blood, plasma or the like, in which cannabinoid is present. Regarding the method of removal, in the case of a column where, for example, the material of the present invention has the form of a fabric and is packed into the column wound around a central axis, a method of removing the cannabinoid by introducing the treatment liquid containing the cannabinoid into the central axis interior and causing it to flow out from holes formed in the central axis to the outside is preferred in terms of efficient adsorption of the cannabinoid.
The material of the present invention can favourably eliminate cannabinoids and it can be suitably employed in applications like the amelioration of reduced blood pressure by use in extracorporeal circulation, etc, in the case of patients showing symptoms of hypotension where cannabinoid blood concentrations are 500 pg or more, in particular 1.0 ng/ml or more.